Bees that consumed natural toxins, such as nicotine and caffeine, from nectar had lower levels of intestinal parasites than those that did not.
A team of scientists looked at hundreds of eastern bumblebees (Bombus impatiens), and their intestinal parasite Crithidia bombi . These parasites are known to shorten the lives of infected bees and lead to problems in the colony, the University of Massachusetts Amherst reported.
The researchers found eight separate toxic chemicals known as secondary metabolites that are produced by plants as a defense mechanism reduced infection levels of the bumblebee parasite by as much as 81 percent in only a week. While the reduction in parasitic infection was not observed to increase the lives of the bees, it most likely reduced the spore load in their feces making the parasite less likely to spread.
"Because plants just sit there and can't run away from things that want to eat them, they have evolved to be amazing chemists. They make biological compounds called secondary metabolites, which are chemicals not involved in growth or reproduction, to protect themselves. They are amazing in the diversity of what they can produce for protecting themselves or for attracting pollinators," said UMass Amherst evolutionary ecologist Lynn Adler.
To make their findings the researchers looked 539 eastern bumblebees suffering from the parasitic infection and allowed them to feed on one of eight natural nectar chemicals or a control nectar; seven days later the parasitic load was measure. The bees involved in the study were taken from a number of colonies to avoid seeing a colony-specific response.
The eight chemicals studied were "nicotine and anabasine found in nectar of flowers in the tobacco family, caffeine from coffee and citrus nectar, amygdalin from almond nectar, aucubin and catalpol from turtlehead flowers, gallic acid from buckwheat nectar and thymol from basswood tree nectar," the researchers reported.
The findings suggest growers who depend on pollinators should consider planting gardens that contain these natural remedies. Researchers are still not sure whether or not the bees are aware of the chemicals' benefits and consume them on purpose.
"That is the million dollar question, the one most often asked when I give talks about these ideas. Unfortunately, it's too early to tell. We just don't know yet," Adler concluded.
The findings were published in a recent edition of the Proceedings of the Royal Society B.
